Secondary impact crushers are usually utilized on site during the construction of roads, dams, buildings, storm sewers and the like to produce an aggregate of desired size from available materials, such as ores, perlite, quartz, marble asphalt mix aggregate, silica and concrete sand. In the building of roads and dams one must frequently make use of materials at hand. Secondary impact crushers provide for utilizing materials at hand to produce aggregate of a particular required size and nature.
The cost of producing a cubical product on site must be less than the cost of shipping it to the site for a secondary impact crusher to be considered an economical alternative for producing the desired product on site. Naturally, those skilled in the art are constantly attempting to lower the cost of producing the product on site from available materials.
Over the years the cost of producing a particular product has been brought down by improvements to various designs and components of secondary impact crushers. Such improvements are exemplified by those shown in U.S. Pat. No. 3,955,767 issued to Mason R. Hise, one of the inventors herein. The improvements set forth in this patent as well as others, such as U.S. Pat. No. 3,970,257 to MacDonald et al, improve the wear life of various components within impact crushers. The apparatus of the invention, as hereinafter disclosed, utilizes various components of novel structure, placement and composition to not only increase the wear life of such components, but to decrease the time and skill needed to reposition, replace and otherwise service such components.
One object of the instant invention is to provide increased component wear life in a secondary impact crusher.
Still another object of the present invention is to minimize on site down time for secondary impact crushers.
Another object of the invention is to provide a more economically operated secondary impact crusher.
Yet another object of the present invention is to better project the housing of a rotating impeller assembly in an impact crusher from abrasion.
One advantage of practicing the present invention is that cost of product is greatly reduced thereby.
Another advantage of the present invention is that an apparatus constructed and operated in accordance therewith is easier to maintain than those of the prior art.